21420010 has 8 divisors (see below), whose sum is σ = 38556036. Its totient is φ = 8568000.

The previous prime is 21420001. The next prime is 21420013. The reversal of 21420010 is 1002412.

It can be written as a sum of positive squares in 2 ways, for example, as 18740241 + 2679769 = 4329^2 + 1637^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Harshad number since it is a multiple of its sum of digits (10), and also a Moran number because the ratio is a prime number: 2142001 = 21420010 / (2 + 1 + 4 + 2 + 0 + 0 + 1 + 0).

It is not an unprimeable number, because it can be changed into a prime (21420013) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1070991 + ... + 1071010.

Almost surely, 2^21420010 is an apocalyptic number.

21420010 is a deficient number, since it is larger than the sum of its proper divisors (17136026).

21420010 is a wasteful number, since it uses less digits than its factorization.

21420010 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2142008.

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 21420010 is about 4628.1756665019. The cubic root of 21420010 is about 277.7196162081.

Adding to 21420010 its reverse (1002412), we get a palindrome (22422422).

The spelling of 21420010 in words is "twenty-one million, four hundred twenty thousand, ten".